The influence of polarization Coulomb field scattering on the parasitic source resistance of E-mode P-GaN/AlGaN/GaN heterostructure field-effect transistors

E-mode P-GaN/AlGaN/GaN heterostructure field-effect transistors (HFETs) of various sizes were fabricated, and their parasitic source resistance (RS) was measured. The measurement results showed that RS varied greatly with changing gate bias, and the degree of RS change also differed with the gate bias of different-sized device samples. Through theoretical analysis, it is found that polarization Coulomb field (PCF) scattering caused by the device process and gate bias can affect electron mobility ( $$\mu_{GS}$$ ) in the gate-source region, which causes the variations in $$\mu_{GS}$$ for different-sized devices and same-sized devices under different gate biases. When $$\mu_{GS}$$ changes with the device size and gate bias, the RS will change accordingly. Our study is the first to discover the gate bias dependency of RS for E-mode P-GaN/AlGaN/GaN HFETs due to PCF scattering, which provides a new idea for further in-depth studies on the RS of E-mode P-GaN/AlGaN/GaN HFETs and device performance optimization.